title: Biochemical characterization of a second family of human Ia molecules, HLA-DS, equivalent to murine I-A subregion molecules.
abstract: In mice, two families of structurally distinct Ia molecules, one designated I-A and the other I-E, have been identified and characterized. The HLA-DR molecules represent one family of human Ia molecules equivalent to the murine I-E molecules on the basis of amino acid sequence homology. We describe the isolation and biochemical characterization of a second family of human Ia molecules, designated HLA-DS for second D-region locus, equivalent to the murine I-A molecules. The human HLA-DS molecules consist of two polypeptide chains, DS alpha (37,000 mol wt) and DS beta (29,000 mol wt), with 73% amino acid sequence identity to the murine I-A molecules. Furthermore, the HLA-DS molecules are closely linked genetically to HLA-DR molecules, a situation analogous to that observed in mice. The similarity in molecular weights of the DR and DS molecules might explain why others have failed to identify the latter in man.
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D000818:Animals; D002143:Callitrichinae; D002460:Cell Line; D006683:HLA-DQ Antigens; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D008285:Major Histocompatibility Complex; D051379:Mice; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis; D013045:Species Specificity; D014357:Trypsin
chemical_list: D006683:HLA-DQ Antigens; D000949:Histocompatibility Antigens Class II; D010446:Peptide Fragments; D014357:Trypsin